1. Field of the Invention
The present invention generally relates to a method for displaying images or pictures on a raster display system controlled by a computer. In particular, the present invention relates to an anisotropic filtering mechanism and to a corresponding device required to reconstruct, scale or subject, to a perspective projection, stored discrete images which will subsequently be also referred to as textures, with high quality on the raster display. In particular, the present invention relates to a method for determining weighting factors for the color calculation of a color value of texels for a footprint.
2. Description of the Related Art
In the prior art, anisotropic filtering methods, such as, for example, the so-called area sampling, are known to associate a texture to a footprint. In the prior art, so-called weighted area samplings and unweighted area samplings are known, a disadvantage of the methods known from the prior art being that discontinuities in the image illustrated are produced with perceivable artifacts at a transition between a weighted and an unweighted sampling.
A “footprint” is the perspective projection of a picture element (pixel) of an object onto a curved surface. A “footprint” can be a convex four-sided (quadrilateral) illustration representing the approximate result of the perspective projection onto a regular texel grid (texture element grid) of a square picture element (pixel) of an object onto a curved surface.